Why does my 2023 GWM Cannon X idle roughly when the air-con is on?

You’d be surprised at how much load an air-conditioner places on an engine, especially when it’s idling and not making much power or torque. It can certainly be enough to make the engine labour and drop revs, forcing it down to a speed where it can no longer idle smoothly; almost as if it’s trying to stall.

Carmakers get around this by programming an idle-up function into the car’s computer. This detects that the air-con has been switched on and will then tell the engine to idle a little faster to keep everything running smoothly. If this idle-up function is not working, you can get the precise symptoms you’ve described. However, if this is the cause then make it GWM’s problem to put right, as it amounts to a fault and should be covered by the new-car warranty.